The specs are close enough. Any cross platform game is going to develop for the lower spec anyway, and you'll be hard pressed to spot the differences. It will all depend on the platform implementation, not the hardware. And so far, both implementations suck, but MS's implementation sucks more, so Sony will probably win this round without some major changes from MS.

I agree that most games will probably look similar in quality... however, when developers eventually do push the hardware... the XBox will likely stutter, while the PS4 will be smooth as silk, by comparison.

DDR3 vs DDR5 for a GPU alone... look at the framerate difference in a budget card with the same GPU running DDR3 vs. DDR5. Then, if the 7790 vs. a 7970 rumor is actually true... there is no contest. Certain developers may take advantage of the PS4's hardware advantages, and we will likely see some games with better visuals on the PS4 than the Xbox One.